Liquid compositions for curing concrete



UNITED STATES PATENT OFFICE 2,441,826 LIQUID COMPDSITIONB FOB CURING CONCRETE Ralph E. Madison, Detroit, Mlcla, assignor 'lrmon Laboratories, Inc., Detroit, Mich, corporation of Michigan No Drawing. Application November 8, 1946, Serial No. 708,797

'5 Claims. 1

This invention relates to improvements in liquid compositions for curing freshly placed Portland cement concrete.

This application is a continuation-inpart of my copending application Serial No. 547,097, which was flied July 28, 1944.

It is well known in the art that certain fllm forming compositions can be applied to the surfaces of freshly placed concrete and prevent or hinder the evaporation of the original mixing water. In other words, the compositions will cause most of the water to be retained in the mass for the necessary purpose of hydration of the cement. Older and more expensive methods of curing, such as sprinkling, ponding, covering with wet earth or burlap or cotton mats, etc., are thereby eliminated. Some of the older curing compositions are disclosed in U. S. patents to Hayden, No. 1,684,671 and Rowan, No. 1,867,421, those in the first patent being characterized by being black in color and those in the second patent being characterized by being clear or transparent. Later compositions are disclosed in U. 8. Patents No. 2,344,579 and No. 2,344,578 to Whitesides, the first referring to black compositions and the second referring to clear or transparent compositions.

The present invention relates to the clear or transparent types. In connection therewith it has been discovered that certain cheap and plentiful resinous materials can be used to make compositions having very good water-retaining properties particularly under the "extreme atmospheric conditions encountered in the laying of concrete roads during the hot summer months. Considered in its broader aspects, the compositions comprise solutions oi a low viscosity resin polymer and rosin or a metallic derivative of rosin in a suitable hydrocarbon solvent.

In particular, the resin polymer may be selected from the class consisting of petroleum hydrocarbon resins of the type which normally exists as a hard, .brittle mass, and are produced by the cracking and repolymerization of selected petroleum distillates, terpene resins made by polymerization of beta-pinene, an alicyclic olefin, and known in the trade as 'Ierpene resin or Piccolyte, and coulnarone-indene resins made by polymerization of coumarone-indene, a mixture of aromatictype oleflns, and known in the trade as Cumar. The term "petroleum resin as used herein is to be understood to be the petroleum hydrocarbon resin defined above. The melting points of the resins employed are approximately 100120 C.

These resins are characterized by being practically unsaponiflable, the saponiflcation number rarely exceeding 5. These resins are further characterized by producing solutions of low viscosity, this latter quality rarely being in excess of thirteen seconds in a No. 4 Ford viscosity cup, when determined on a 40% solution of the resin. It will be noted that all of the above resins are polymers of various hydrocarbon olefins resulting in hard, brittle masses as contrasted to the plastic or elasticbodles that can be made from the same type of olefin under diiferent conditions and. therefore. may be broadly referred to as hard resins of the olefin type.

The petroleum hydrocarbon resin manufactured and sold by the Velsicol Corporationand identified by the manufacturer as "Velsicol AB 11-8" is a typical petroleum resin coming within the scope of this invention. This particular petroleum resin and other resins of this type having similar physical and chemical properties are preeminently suited for use in compositions for curing concrete, and tests have demonstrated that compositions containing them have unexpectedly good water retaining properties. "Velsicol AB 11-8 is a methylated indene-methylated styrene type resin which normally exists as a hard. brittle mass and forms solutions of low viscosity, melting at approximately -120 0., and having a molecular weight in the range of 500-2000, said resin having been produced by the cracking and repolymerization of selected petroleum distillates.

The rosin may be from the class of wood or gum rosins. It may be a physically treated rosin as in U. S. Patent No. 1,643,276 to Logan and known in the trade as Bolros, or a chemically treated rosin known as "Poly Pale Rosin." Further it may be a calcium or zinc salt of the resins mentioned before.

The calcium rosinate may be a compound known in the art as "limed rosin. made by slowly adding approximately 5% of lime to rosin maintained in a molten condition at approximately 500 F., and allowing the reaction to proceed until most of the foaming has subsided. This ma terial will have an acid number of approximately 96.

The zinc rosinate may be produced by refluxing a solution of resin in the presence of zinc oxide until the latter is reacted. One commercial variety of zinc rosinate employs enough zinc oxide to produce an acid number of approximately 15. Another variety uses an excess of zinc oxide in which case the acid number is zero or actually less, the material thus being on the alkaline side.

assassin As stated before. the various nonmetallic rosins have been used with an acid number ranelna from approximately 145 to 175, limed rosins with an acid number approximately 96, and the various zinc treated rosins with an acid number ranging from to less than zero. It is to be understood that for the purposes of this invention these materials are equivalents. Solutions of all oi. these rosins and metallic derivatives have been used in combination with solutions of the three resins disclosed and it has been found that, under the same conditions of testing, practically equal water retention qualities are obtained. The reasons for selecting a particular material will arise from considerations of availability, cost, color, viscosity. drying time, etc. For instance, the physically treated rosins comprise some dark colored materials, which, however, are quite cheap. The chemically treated rosins usually are lighter in color and also have a higher melting point which is an aid in rapid drying to a solid film, but these rosins are relatively high in cost. Limed rosin can be either light or dark, has a fairly high melting point, and is widely available. The zinc resins are widely available, are light in color and, as in the case or limed rosin, produce solutions or rather high viscosity. This latter property is desirable when the curing compound is to be used on a vertical or steeply inclined surface, the high viscosity materially tending to prevent the compound irom flowing or running off the surface.

Any suitable hydrocarbon solvent may be used. Typical examples are petroleum or coal tar solvents or combinations thereof selected from the group V. M. P. naphtha-distillation 200-300 F., mineral spirits-distillation 290-4l0 F., toluene, xylene, etc. The preferred solvent or combination is that which will have a distillation range 01' approximately il-300 F., although it is not limited to this range.

The invention relates to the specific discovery that when certain amounts of solutions oi the rosins or metallic rosin derivatives are added to solutions of the particular resins hereinabove described, the water-retaining properties are very considerably greater than when either the rosin or metallic rosin derivatives, or the resins, are used alone. At the present time it is not fully comprehended why the addition of these elements to solutions of the three classes of resins disclosed. has such a signal eflect on the water retention qualities. It is well known that freshly placed concrete is alkaline and that rosin and its metallic derivatives are chemically affected by a]- kaii. A plausible theory is that the alkali in the fresh concrete does react to a certain extent with the rosin or metallic derivative to produce a certain number of "anchor points" which act to hold the deposited film smoothly in place. This view is supported by the fact that ii solutions of the resins alone, or of the rosins or metallic derivatives alone are applied in the normal manner to surfaces oi freshly placed concrete, there usually will result a considerable amount or cracking or curling up of the deposited films. Since smooth films are obtained when the combinations are used, it is indicated that a certain amount oi anchoring is taking place. While it is not desired that the invention be limited by this explanation, it nevertheless seems to be adequate. In other words, with a resin solution alone there are no forces present to prevent the resin from cracking and curling up when the solvent has evaporated. And with the solutions 0! rosin 4 or metallic rosin derivatives alone, there seems to be so much chemical reaction taking place that all iilm-iorming properties have been destroyed.

It should be pointed out also that the common element in all the rosins and metallic derivatives oi the rosins used is abietic acid, whether in its natural form, its isomeric forms. or its p lymerized forms; or whether in the metallic derivatives or abietic acid in its natural form. its isomeric i'orms or its polymerized forms. Further by way oi contrast, it has been determined that the glycerine esters oi abietic acid when used in the invention do not produce the same beneficial eflect. Since these latter materials are but very slightly aflected by the alkaline elements of concrete and do not produce beneficial results. it would appear that the limited amount of reaction product or the alkaline elements oi concrete and abietic acid. or the metallic derivatives oi abietic acid, is in some way responsible for the unexpected results.

One embodiment of the invention is 32 pounds of petroleum resin, 8 pounds of physically treated wood rosin and pounds of V. M. P. naphtha and 10 pounds oi xylene. Still another example is 32 pounds of petroleum resin, 8 pounds of zinc rosinate, 50 pounds oi V. M. P. naphtha and 10 pounds of xylene. The same examples may be used in which terpene resin is substituted for petroleum resin. The some examples may also be used in which coumarone-indene resin is substituted for petroleum resin and in which 20 parts oi xylene are used with 40 parts of naphtha for better solvency.

It is pointed out that any suitable combinations or the resins and rosins or rosin derivatives may be used; the optimum quantities being approximately 32 pounds oi combined resin, approximately 8 pounds of combined rosins or metallic rosin derivatives. and approximately pounds 01' solvent, selected to provide the solvency required by the resins employed and having a distillation range of approximately 200-300 F.

The amount of resin in the non-volatile part 01' the composition may be varied between approximately 32 and 24 pounds and the rosin or metallic rosin derivatives between 8 and 16 pounds, Further the combined amount of resin and rosin or metallic rosin derivative may be varied between approximately 35 to 57 pounds and the solvent between and 43 pounds. When the combined resin and rosin or metallic rosin derivative exceeds approximately 57 pounds the viscosity will have a tendency to rise to such an extent that the material will be difllcult to apply by spraying methods. When the combined resin and rosin is less than approximately 25 pounds the viscosity tends to become so low that excessive penetration into the surface layers of the concrete will occur, thus producing a somewhat discontinuous him with greatly reduced water-retaining properties.

Having thus shown several examples 0! the compositions which may embody the invention, a table is hereinafter set out giving results of water retention tests expressed in grams of water loss at the end of seven days. The tests were made under a. well-known variation of A. S. 'I. M. Designation Cl56-40'I, "Method for Determinin the Emciency of Concrete Curing Materials as outlined below. It is presently held by those versed in the art that a satisfactory curing compound should not lose more than 5.0 grams of water under this test.

Procedure-Small test molds shall be filled with mortar and treated with curing compound and the water loss due to evaporation through the curing compound shall be determined at one and .on a laboratory scale. perpendicular to spray tubes.)

(Adjust tip so that it is Calculate the number of grams necessary to cover the pan and rim of the molded specimen at a rate of 200 square seven days. Details of testing procedure follow: 5 feet per gallon. Attach sprayer to a suitable (a) Composition of marten-6 pounds sand, compressed air supply, using approximately six 2 pounds cement, and sufl'icient water to produce pounds air pressure per square inch and spray 50% iiow. curing compound evenly onto the surface. De-

The sand shal1 be dry and graded in accordtach the air line at intervals and weigh the spray ance with A. S. T. M, Designation: C156-40T. gun and contents. Spraying should be continued The cement shall be normal Portland. The flow until the calculated weight has been applied to shall be measured in accordance with A. S. T. M. the surface, The weight of solid material on each Designation: (2-87. specimen is determined by spraying the same (b) Molds.The molds shall be small pie pans quantity as used on the mortar specimens onto approximately 6 inches in diameter and inch empty pans weighed for tare and placed in the deep. The weights shall be recorded prior to cabinet with the mortar specimens and refilling with mortar. weighed at twenty-four hours.

(0) Mixina.-Sand and cement shall be mixed (1) Storage of specimens.lmmediately after dry till uniform and then water as predetermined application the specimens are placed in a cabinet for 50% flow shall be added and ingredients mixed maintained at 100 F., plus or minus 1 and relaby hand for 1V2 minutes, using rubber gloves. The t ve u i ity of 30%, P1118 0 i us 3%. quantity of material shall be sufficient to yield The relative humidity can be maintained by 20% more material than necessary to fill six filling humidity control pan with saturated magmolds. No more than six pans shall be filled from nesium chloride solution. The pan should be y one mix, painted with a coal-tar paint to prevent reac- (d) Molding.-The molds shall be filled, tion between the magnesium chloride and the tamped, and wood floated to a uniform surface zinc coating on the pan. level with the rim except for a shallow trench Periodic checks should be made on the relative along the rim. The rim shall then be wiped clean humidity by means other than the wet and dry and th specimen weighed bulb thermometers supplied with the cabinet.

(e) Preliminary storage.-Store specimens in a For p a mom! driven m te ay cabinet maintained at 100 F., plus or minus 1 be operated for a few minutes inside the cabinet, and 30% relative humidity, plus or minus 3% for but not o nough to raise the humidity due 60 to 90 minutes. to water evaporation from the hygrometer itself.

(1) Preparation of surface.Remove specimens Further control, if necessary. can be obtained by from preliminary storage cabinet. Brush surface s n c c ch Means s e P ded lightly to remove laitance and wipe rims clean to prevent the calcium chloride solution formed again. Immediately return specimens to cabinet. from ng th the magnesium chloride solu- (a) Application of compound.--After an addition. tional 30 minutes in the cabinet, specimens shall (1) Calculation of water retention-Weigh be removed and weighed and the trench filled pans at stated intervals, Loss of water is calcuwith sealing compound to form a bead slightly lated on the amount of water in the mortar at above the surface of the pan. The sealed specitime 01' pp o o curing omp ndmen shall again be weighed and the curin com- The compositions of the materials listed in pound applied immediately at arate of 200 square Table I below show the preferred embodiments feet per gallon, using a nasal sprayer. The proof the invention. The variations and limits from cedure outlined above is such that the surface a standpoint of water retention are shown in water sheen has disappeared and no cracks have further tables. "Velsicol AB 11-8 was employed formed at the edge of the specimen. in all of the tests where a petroleum resin was ()1) Spray procedurc.Fiil the spray jar apso used inasmuch as it is representative of the hardproximately two-thirds full with curing comtype petroleum resins coming within the scope pound. Attach the spray tubes and tip and weigh of this invention.

Tsar: I

C'ompositions of preferred materials Y Pounds 0i Grams of Pounds Lbs. oi N o. T of Resin T of Rosin or Derivative Rosin or Type of Sch ent Water ype Resin ype Derivative Solvent Loss 1 Petroleum 32 Physically treated rosin 8 i fi jj l fi i fjf :l. 3 s2 5% limed rosin s l .1 32 Zinc rosinate B 4. 7 32 Chemically treated rosin 8 .l. 3 Physically treated rosin 8 m 3. i 32 5% limed rosin 8 m .l. 2 32 Zinc Rosinate Acid No. 15.. 8 Hi L9 32 (Themically treated rosin. B 00 2. Ii 32 Physically treated rosin 8 3g 4. ii 10 ..rio s2 5% iinied rosin a {,3 3 11 .do 32 Zinc Rosinate Acid No. 15.. 8 38 5.0 12 .do 32 Chemically treated rosin 8 3g 3. 4

' Tenn 1].

Composition: using resins alone, and resin; or metallic roainote: alone Pounds oi Grllfllo! Pounds Lbs. oi ill in '1 oi Rosin or Derivative Rosinor T of Solvent Watt No an M Derivative his rs Petroleum m o TP 'ff: :3 an n oumaronelndene..-- 4o o ,5,- Yflf'fffffi: ,3 not 40 0 V. M. P. Naphtha. on 1.75 0 Chemically treated rosin 40 .....Lo 6i) .0 i) Physically treated rosin 40 on 18. 7 0 Gum Rosin 40 on. 25.1 0 %l1madroslnaold No.06 40 00 10.8 0 Zinc rosinate acid No 40 60 .6 0 Zinc rosinate scidNo.0(minus)- 40 G0 0.8

Test: II!

Table showing limiting compositions Pounds oi Grams of Pounds Lbs. o! No. Type of Resin Ream Type of Rosin 0r Derivative Dlzrfliivlgtiilva Type 0! Solvent solvent Water a l Petroleum 36 Physically treated rosin 4 g 6.3 l "I10 32 ...do a z; do as do 12 {g as 24 .do 24 ..-do is ,g 4.1 25 .do 20 ..-.do 2o :8 5.4

so M xtsss f:.if?fff:::: i3 M 2-; do 45.6 .do 11.4 3.1 1 do 32 -..do s {3 as 28 .110 28 do 1 {1 4.6 20 "do so .do s m In order to demonstrate the critical nature of Gardner-Holdt vis. (varnish series) D-E those petroleum resins which are operative in the Flash, 000, F 20$ present invention, comparative tests were made Fire, 000, F 220 using "Velsicol AB 11-8" and another type oi. pe- Pour point, F -30 troleum resin which is produced by polymeriza- Color (polymer method) 5% tion oi unrefined vapor phase cracked gasoline. Percent nonvolatile 87.5 normally exists as a thick. viscous resinous mate- Iodine number, WIJS 202 rial and has different physical and chemical properties which render it entirely unsuited for the present invention. The particular petroleum resin known to the trade as "Phillips Drying Oil, Grade I" was selected for purposes of comparison since it appears to be representative oi the normally viscous petroleum resins. The specifications of "Phillips Drying 011, Grade I" appear in Table IV below:

Tana: IV

Gravity, API 16.2 A. S. '1. M. Distillation:

I. B. P., "I" 222 5% cond. 402 10 424 20 458 Percent cond. at 450 F 18 Viscosity:

B. U. V. 100 F "224 8. U. V. 210 1" 46 In making the tests, two discrete compositions were compounded each consisting oi a petroleum resin, a rosin and a solvent. The compositions were identical except that one contained a viscous resin (Phillips Drying Oil, Grade I) and the other contained a hard petroleum resin of the type coming within the scope of the instant invention (Velsicol AB 114). Identical amounts of materials were used in the two compositions. and in both instances the proportions were within the ranges specified for the instant invention (column 4). The tests were made according to the standard A. B. T. M. procedure described in columns 5-6 and the results appear in Tables V and VI below. Table V shows the results observed from three specimens 01' the composition made from a hard-type petroleum resin and Table VI shows the results observed irom three specimens 01' the composition made from the normally vie,-

" cons-type petroleum resin.

Tau V Specimen No cars w 0270 Loss in Loss in Losln Loss in Loss in Grams Per Cent Grams Per Cent Grams Per Cent Weight at Molding 504. 5 562. Weight 46. l 45. Weight 0! 517. 4 ate: in M 50. 2 Wgt. before Brushing 500. 558.3 Wgt. alter Brush 550. 557. 3 Wgt. before Sealing 550. 557. 3 after 509. 567. 5 Wgt. at start cure... 568. 566. 1 Watt loss before cute 5. 5. 6 Wgt. oi Curing Comd 3. 2 3. 2 3. 2 551d! in Curing Comp--. 1. 1 1. l l. l

""ifo 1. 1 3. 9 3. 2 7. 3

TABLE VI Specimen No 6265 6266 6267 Loss in Loss in Loss in Loss in Loss in Loss in Gms. Per cent Gms. Per cent Gms. Per cent Weight at Molding 573. 9 55B. 5 564. 4 W ht 45. 2 44. l 513. 3 520. 3 53. 50. 7 5i. 7 553. 7 561. 0 552. 9 550. 2 552. 9 500. 2 563. 6 571. 2 Wgt at start cure. 563. 2 570.0 Water loss before cure 5. i 5. 2 Wgt. of Curing Compound 3.2 3.2 3.2 Solids in Curing Comp--. 1.0 1.0 1.0

Corrected Weight 579. 8 564. 2 571. 0 1 Day.. 562. 0 l7. 8 37 547. 9 16.3 35. 8 552. 8 l8. 2 39. l 3 Days... 558. 2 21.0 544. 0 20. 2 44. 3 548. 9 22. 1 4746 7 Days 555. l 24. 7 51. 5 540. 5 23. 7 52. 0 545. 5 25. 5 55.0

As suggested, 5 grams of water loss in seven days is considered the maximum allowable under the test. The fact that all three of the specimens listed in Table VI had lost at least 16.3 grams of water by the end of the first day indicates that the viscous petroleum resin used therein is entirely unsuited for use in a concrete curing compound and that it cannot be considered an equivalent of the hard petroleum resin used in the specimens listed in Table V. In contrast, the superlative qualities of the hard petroleum resin are conclusively established by the fact that none of the specimens listed in Table V lost more than 3.2 grams of water in seven days.

Having thus described my invention, what I claim by Letter Patent is:

1. A liquid composition for curing freshly placed concrete comprising from 28 to 46 parts or a material selected from the class consistin of coumarone-indene resin melting at approximately 100-120 C.. terpene resin melting at approximately 100-120 0.. and a methylated indenemethylated styrene resin which normally exists as a hard brittle mass and forms solutions of low viscosity, melting at approximately IOU-120 C., and having a molecular weight in the range of 500-2000, said resin having been produced by the cracking and repolymerization 01 selected petroleum distillates; from 7 to 11 parts of a rosin material selected from the class consisting of rosin, calcium rosinate and zinc rosinate; and from 64 to 43 parts of a volatile hydrocarbon solvent.

2. A liquid composition for curing freshly placed concrete comprising from 28 to 46 parts of a methylated indene-methylated styrene resin which normally exists as a hard brittle mass and forms solutions of low viscosity, melting at approximately -120 C., and having a molecular weight in the range of 500-2000, said resin having been produced by the cracking and repolymerization of selected petroleum distillates; from 7 to 11 parts of a rosin material selected from the class consisting oi rosin. calcium rosinate and zinc rosinate; and from 64 to 43 parts of a volatile hydrocarbon solvent.

3. A liquid composition for curing freshly placed concrete comprising from 28 to 46 parts of coumarone-indene resin melting at approximately IOU- C.; from 7 to 11 parts of a rosin material selected from the class consisting of rosin, calcium rosinate and zinc rosinate; and from 64 to 43 parts of a volatile hydrocarbon solvent.

4. A liquid composition for curing freshly placed concrete comprising from 28 to 46 parts of terpene resin melting at approximately 100- 120 0.; from 7 to 11 parts 01 a resin material selected from the class consisting of resin, calcium rosinate and zinc rosinate; and from 64 to 43 parts of a volatile hydrocarbon solvent.

5. The method 01. treating freshly placed concrete to inhibit evaporation of moisture which consists of coating the surface of the concrete with a substance comprising from 28 to 46 parts menace ll 0! I. matericl selected iron the cless conslstins ed coumsrone-indene resin melting st epproximstely 100-120 0.: terpene resin meltins at approximately lilo-120 0.; and a. methyllted lndenemethylated styrene resin which normally exists I as a herd brittle mass and terms solutions or low viscosity, melting at approximately 100-120 0., and having a molecular weisht in the reuse 01' 500-2000, said resin having been produced by the cracking and repoLvmerizetion of selected petrol0 leum distillstes: irom '7 to 11 parts 01 a rosinmsteriel selected from the class consisting of resin,

celciumrosinnteendslncroeinetqendtrom 1:048 parts of svcletile hydrocarbon solvent.

RALPH E. MADISON.

REFERENCES CITED The iollowin references are of record in the file 01' this patent:

UNITED STATES PATENTS Certificate of Correction Patent No. 2,441,826.

RALPH E. MADISON It is hereby certified that error appears in the rinted specification of the above numbered patent requiring correction as follows: olumns 5 and 6, Table 1, item number 5, under the subheading Pounds Resin insert the numeral 82; end that the said Letters Patent shouldbe read with this correction therein that the some may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 20th day of July, A. D. 1948.

THOMAS F. MURPHY,

Assistant oommt'est'mler of Patents.

menace ll 0! I. matericl selected iron the cless conslstins ed coumsrone-indene resin melting st epproximstely 100-120 0.: terpene resin meltins at approximately lilo-120 0.; and a. methyllted lndenemethylated styrene resin which normally exists I as a herd brittle mass and terms solutions or low viscosity, melting at approximately 100-120 0., and having a molecular weisht in the reuse 01' 500-2000, said resin having been produced by the cracking and repoLvmerizetion of selected petrol0 leum distillstes: irom '7 to 11 parts 01 a rosinmsteriel selected from the class consisting of resin,

celciumrosinnteendslncroeinetqendtrom 1:048 parts of svcletile hydrocarbon solvent.

RALPH E. MADISON.

REFERENCES CITED The iollowin references are of record in the file 01' this patent:

UNITED STATES PATENTS Certificate of Correction Patent No. 2,441,826.

RALPH E. MADISON It is hereby certified that error appears in the rinted specification of the above numbered patent requiring correction as follows: olumns 5 and 6, Table 1, item number 5, under the subheading Pounds Resin insert the numeral 82; end that the said Letters Patent shouldbe read with this correction therein that the some may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 20th day of July, A. D. 1948.

THOMAS F. MURPHY,

Assistant oommt'est'mler of Patents. 

